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Demonstrations › Liquids & Intermolecular Forces

Lecture Demonstrations

Liquids & Intermolecular Forces

Cooking oil and water are used to illustrate that polar and non-polar substances do not mix. When dish soap is added, an emulsion is created by allowing the dispersion of oil into water.

 

The polarity and solubility of iodine are demonstrated. When iodine is added to water it is virtually insoluble. When it is added to methylene chloride it dissolves, turning the solution pink. When iodine is added to an aqueous solution containing iodide ions, the iodine dissolves producing a brown solution.

 

When a 1 L bottle is shaken, the blue and white beads mix within the liquid as expected. However, when allowed to settle, the beads separate, white at the top and blue at the bottom. Shortly, the two separated colored beads slowly come together until they meet in the center of the liquid, white on top of blue. The mixing and separating can be observed over and over.

 

Water is boiled at room temperature due to a decrease in pressure

 

A paper clip floats on water. Dish soap is added and the paper clip sinks.


A paper towel or filter paper is dipped into water and the water travels up the paper.

 

A stream of water is “bent” upon interaction with a statically charged glass rod.

 

Liquid oxygen is produced by the condensation of oxygen gas onto a metal coffee can full of liquid nitrogen, and then collecting it into a Styrofoam cup. The blue color of liquid oxygen is observed and the magnetic properties demonstrated.